1895.] Aquatic Fungi. 437 
water; but some of them at least begin to creep with amoe- 
boid movements over the surface of the antheridium and 
thence over the oogonium, the single cilium projecting out- 
ward somewhat obliquely. In this way they may take jour- 
neys of considerable length, creeping around the oogonium, 
down to the hypha which bears it, and then back again; some- 
times disengaging themselves and swimming away as already 
described. 
In the meantime, usually after about one-third of the an- 
therozoids have made their escape, the oogonium, having 
reached maturity, opens. Before this occurs the main body 
of the organ is filled by a mass of very coarsely granular pro- 
toplasm, its projecting neck being filled with a more finely 
granular contents which also extends around the coarser mass. 
granular content is also discharged, which, instead of be- 
coming at once dissipated in the surrounding water like the 
finely granular protoplasm, coheres in aspherical mass and 
exercises an attractive influence on passing antherozoids (fig. 
5). After the dehiscence of the oogonium its remaining con- 
tents contract into an oosphere of definite contour (figs. 4, 5) 
which is then ready for fertilization. The antherozoids soon 
creep upoverthe neck and through the opening at its tip, making 
their way into the oogonium and moving along its inner wall 
down to the oosphere. As many as eight antherozoids have 
been seen in a single oogonium; but only one appears to 
fuse with the oosphere in the fashion described by Cornu, 
the cilium projecting upwards and the body slowly sinking 
into the substance of the oosphere (fig. 5). In some instances 
an antherozoid which has just escaped from the antheridium 
may be seen to stretch across to the adjacent tip of the oogo- 
nium into which it makes its entrance without the usual pre- 
liminary perambulations. Fertilization having been thus ac- 
complished, the oospore surrounds itself with a smooth thick 
wall, and, in both the species under consideration, remains 
within the oogonium at maturity. Although the oospores have 
been kept in water for several weeks, no signs of germina- 
tion have been as yet observed; but it seems more than prob- 
